This invention relates to a buckle assembly for a seat belt used as a safety belt provided for a motor vehicle or aircraft and, more particularly, a buckle assembly for a push button type seat belt.
Buckles of this type commonly used have been disclosed in Japanese Patent Laid-Open Publication Nos. 60-18102, 60-75004 and 60-75005. In this type of buckle, locking is effected when a latch engages a latch engaging bore formed on its tongue by inserting the tongue into a buckle body, whereby withdrawal of the tongue is prevented.
Further, in this type of seat belt buckle, the tongue is at first inserted fully into the buckle body, so that, after locking is effected, the latch engagement of the tongue cannot be released and the locking position is securely maintained even if a shock has been applied to the buckle, and furthermore a push button for removing the latch engagement may be pressed by applying only a slight pressure. After the locking is released by pressing the push button, the tongue that is now freed from the latch engagement may be pulled out from the buckle body.
Spring components of complicated shapes are held in the buckle body of a conventional seat belt buckle in order to bring the push button back to its original position, as well as to push (press) the latch continuously toward its locked position.
Since, however, the spring components in the conventional seat belt buckles are formed into complicated spring shape, controlling of the spring components has been difficult, hindering the automated assembling of the belt buckle.
There is also a type, such as indicated in Japanese Utility Model Laid-Open Publication No. 61-194311, in which a double torsional coiled spring is used as the spring component incorporated into a seat belt buckle, for pressing the push button to bring it back toward its original position as well as for pushing the latch toward its locked position using this coiled spring.
Because, in the conventional seat belt buckle using a double torsional coiled spring, the latch is pressed by engaging each free end of the cantilever of the coiled spring with the latch, it is difficult to let the spring force of the coiled spring act on the latch in a well balanced manner, and because each movable end of the coiled spring is individually engaged with the latch and its position is determined after the double torsional part of the coiled spring has been inserted into a retaining pin to be retained, assembling of the double torsional coiled spring is difficult, hindering the automatic assembling of the seat belt buckle.
Moreover, the seat belt buckle described in Utility Model Laid-Open Publication No. 61-194311 is with a risk such that, when the cover is removed, the push button may be also removed from the retaining groove of the base body, if being shocked for some reason, that is, a seat belt buckle with the push button released does not function as a buckle.